Species Gafna
Group Dusk
Appearance A large, red and brown Gafna with small, sharp horns. Often wore a saddle for riding.
Status Deceased
Creator The Original Munki

Riku was a Gafna (a rodent-like Rahi) created by member The Original Munki.

Aktamu's pet Gafna, Riku was a loyal and helpful, if sometime a bit temperamental, companion. He was often lazy, but the promise of a delectable madu fruit was likely to persuade him to do anything.

Riku would sometimes accompany Aktamu on adventures with the Dusk, and sometimes slept in the Dusk base in Po-Metru. To the Gafna's dismay, he and his master were separated when Aktamu was captured and taken to Ko-Isa. Riku later accompanied some of the Dusk on missions out to the Isas, always longing to find his lost Matoran friend.

In a battle with the Dawn on Po-Isa, Riku threw himself in front of a dagger thrown by Nin, which would otherwise have killed one of the Dusk. The dagger pierced his heartlight, killing him.

Riku's death was one of the driving factors that caused Aktamu to go somewhat insane, attempting to get revenge on Nin and accidentally murdering three Matoran.